linux-toradex.git/include/linux/platform_device.h, branch v6.16-rc6

Get rid of 'remove_new' relic from platform driver struct

2024-12-01T23:12:43+00:00

The continual trickle of small conversion patches is grating on me, and
is really not helping.  Just get rid of the 'remove_new' member
function, which is just an alias for the plain 'remove', and had a
comment to that effect:

  /*
   * .remove_new() is a relic from a prototype conversion of .remove().
   * New drivers are supposed to implement .remove(). Once all drivers are
   * converted to not use .remove_new any more, it will be dropped.
   */

This was just a tree-wide 'sed' script that replaced '.remove_new' with
'.remove', with some care taken to turn a subsequent tab into two tabs
to make things line up.

I did do some minimal manual whitespace adjustment for places that used
spaces to line things up.

Then I just removed the old (sic) .remove_new member function, and this
is the end result.  No more unnecessary conversion noise.

Signed-off-by: Linus Torvalds

platform: Make platform_bus_type constant

2024-09-03T11:00:50+00:00

Since commit d492cc2573a0 ("driver core: device.h: make struct
bus_type a const *"), the driver core can properly handle constant
struct bus_type, move the platform_bus_type variable to be a constant
structure as well, placing it into read-only memory which can not be
modified at runtime.

Cc: Greg Kroah-Hartman 
Suggested-by: Greg Kroah-Hartman 
Signed-off-by: Kunwu Chan 
Link: https://lore.kernel.org/r/20240823075544.144426-1-kunwu.chan@linux.dev
Signed-off-by: Greg Kroah-Hartman

platform: Make platform_driver::remove() return void

2024-05-27T08:34:35+00:00

struct platform_driver::remove returning an integer made driver authors
expect that returning an error code was proper error handling. However
the driver core ignores the error and continues to remove the device
because there is nothing the core could do anyhow and reentering the
remove callback again is only calling for trouble.

To prevent such wrong assumptions, change the return type of the remove
callback to void. This was prepared by introducing an alternative remove
callback returning void and converting all drivers to that. So .remove()
can be changed without further changes in drivers.

This corresponds to step b) of the plan outlined in commit
5c5a7680e67b ("platform: Provide a remove callback that returns no value").

Signed-off-by: Uwe Kleine-König

platform: Provide stubs for !HAS_IOMEM builds

2023-07-18T14:19:00+00:00

The various _ioremap_resource functions are not built when
CONFIG_HAS_IOMEM is disabled but no stubs are provided. Given how
widespread IOMEM usage is in drivers and how rare !IOMEM configurations
are in practical use let's just provide some stubs so users will build
without having to add explicit dependencies on IOMEM.

The most likely use case is builds with UML for KUnit testing.

Reviewed-by: Greg Kroah-Hartman 
Reviewed-by: David Gow 
Reviewed-by: Takashi Iwai 
Signed-off-by: Mark Brown 
Link: https://lore.kernel.org/r/20230718-asoc-topology-kunit-enable-v2-2-0ee11e662b92@kernel.org
Signed-off-by: Mark Brown

platform: Provide a remove callback that returns no value

2023-01-17T18:04:17+00:00

struct platform_driver::remove returning an integer made driver authors
expect that returning an error code was proper error handling. However
the driver core ignores the error and continues to remove the device
because there is nothing the core could do anyhow and reentering the
remove callback again is only calling for trouble.

So this is an source for errors typically yielding resource leaks in the
error path.

As there are too many platform drivers to neatly convert them all to
return void in a single go, do it in several steps after this patch:

 a) Convert all drivers to implement .remove_new() returning void instead
    of .remove() returning int;
 b) Change struct platform_driver::remove() to return void and so make
    it identical to .remove_new();
 c) Change all drivers back to .remove() now with the better prototype;
 d) drop struct platform_driver::remove_new().

While this touches all drivers eventually twice, steps a) and c) can be
done one driver after another and so reduces coordination efforts
immensely and simplifies review.

Signed-off-by: Uwe Kleine-König 
Link: https://lore.kernel.org/r/20221209150914.3557650-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman

Merge tag 'driver-core-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2022-06-03T18:48:47+00:00

Pull driver core updates from Greg KH:
 "Here is the set of driver core changes for 5.19-rc1.

  Lots of tiny driver core changes and cleanups happened this cycle, but
  the two major things are:

   - firmware_loader reorganization and additions including the ability
     to have XZ compressed firmware images and the ability for userspace
     to initiate the firmware load when it needs to, instead of being
     always initiated by the kernel. FPGA devices specifically want this
     ability to have their firmware changed over the lifetime of the
     system boot, and this allows them to work without having to come up
     with yet-another-custom-uapi interface for loading firmware for
     them.

   - physical location support added to sysfs so that devices that know
     this information, can tell userspace where they are located in a
     common way. Some ACPI devices already support this today, and more
     bus types should support this in the future.

  Smaller changes include:

   - driver_override api cleanups and fixes

   - error path cleanups and fixes

   - get_abi script fixes

   - deferred probe timeout changes.

  It's that last change that I'm the most worried about. It has been
  reported to cause boot problems for a number of systems, and I have a
  tested patch series that resolves this issue. But I didn't get it
  merged into my tree before 5.18-final came out, so it has not gotten
  any linux-next testing.

  I'll send the fixup patches (there are 2) as a follow-on series to this
  pull request.

  All have been tested in linux-next for weeks, with no reported issues
  other than the above-mentioned boot time-outs"

* tag 'driver-core-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (55 commits)
  driver core: fix deadlock in __device_attach
  kernfs: Separate kernfs_pr_cont_buf and rename_lock.
  topology: Remove unused cpu_cluster_mask()
  driver core: Extend deferred probe timeout on driver registration
  MAINTAINERS: add Russ Weight as a firmware loader maintainer
  driver: base: fix UAF when driver_attach failed
  test_firmware: fix end of loop test in upload_read_show()
  driver core: location: Add "back" as a possible output for panel
  driver core: location: Free struct acpi_pld_info *pld
  driver core: Add "*" wildcard support to driver_async_probe cmdline param
  driver core: location: Check for allocations failure
  arch_topology: Trace the update thermal pressure
  kernfs: Rename kernfs_put_open_node to kernfs_unlink_open_file.
  export: fix string handling of namespace in EXPORT_SYMBOL_NS
  rpmsg: use local 'dev' variable
  rpmsg: Fix calling device_lock() on non-initialized device
  firmware_loader: describe 'module' parameter of firmware_upload_register()
  firmware_loader: Move definitions from sysfs_upload.h to sysfs.h
  firmware_loader: Fix configs for sysfs split
  selftests: firmware: Add firmware upload selftests
  ...

bus: platform,amba,fsl-mc,PCI: Add device DMA ownership management

2022-04-28T13:32:20+00:00

The devices on platform/amba/fsl-mc/PCI buses could be bound to drivers
with the device DMA managed by kernel drivers or user-space applications.
Unfortunately, multiple devices may be placed in the same IOMMU group
because they cannot be isolated from each other. The DMA on these devices
must either be entirely under kernel control or userspace control, never
a mixture. Otherwise the driver integrity is not guaranteed because they
could access each other through the peer-to-peer accesses which by-pass
the IOMMU protection.

This checks and sets the default DMA mode during driver binding, and
cleanups during driver unbinding. In the default mode, the device DMA is
managed by the device driver which handles DMA operations through the
kernel DMA APIs (see Documentation/core-api/dma-api.rst).

For cases where the devices are assigned for userspace control through the
userspace driver framework(i.e. VFIO), the drivers(for example, vfio_pci/
vfio_platfrom etc.) may set a new flag (driver_managed_dma) to skip this
default setting in the assumption that the drivers know what they are
doing with the device DMA.

Calling iommu_device_use_default_domain() before {of,acpi}_dma_configure
is currently a problem. As things stand, the IOMMU driver ignored the
initial iommu_probe_device() call when the device was added, since at
that point it had no fwspec yet. In this situation,
{of,acpi}_iommu_configure() are retriggering iommu_probe_device() after
the IOMMU driver has seen the firmware data via .of_xlate to learn that
it actually responsible for the given device. As the result, before
that gets fixed, iommu_use_default_domain() goes at the end, and calls
arch_teardown_dma_ops() if it fails.

Cc: Greg Kroah-Hartman 
Cc: Bjorn Helgaas 
Cc: Stuart Yoder 
Cc: Laurentiu Tudor 
Signed-off-by: Lu Baolu 
Reviewed-by: Greg Kroah-Hartman 
Reviewed-by: Jason Gunthorpe 
Reviewed-by: Robin Murphy 
Tested-by: Eric Auger 
Link: https://lore.kernel.org/r/20220418005000.897664-5-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel

amba: Stop sharing platform_dma_configure()

2022-04-28T13:32:20+00:00

Stop sharing platform_dma_configure() helper as they are about to have
their own bus dma_configure callbacks.

Signed-off-by: Lu Baolu 
Reviewed-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/20220418005000.897664-4-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel

driver: platform: Add helper for safer setting of driver_override

2022-04-22T15:13:53+00:00

Several core drivers and buses expect that driver_override is a
dynamically allocated memory thus later they can kfree() it.

However such assumption is not documented, there were in the past and
there are already users setting it to a string literal. This leads to
kfree() of static memory during device release (e.g. in error paths or
during unbind):

    kernel BUG at ../mm/slub.c:3960!
    Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
    ...
    (kfree) from [] (platform_device_release+0x88/0xb4)
    (platform_device_release) from [] (device_release+0x2c/0x90)
    (device_release) from [] (kobject_put+0xec/0x20c)
    (kobject_put) from [] (exynos5_clk_probe+0x154/0x18c)
    (exynos5_clk_probe) from [] (platform_drv_probe+0x6c/0xa4)
    (platform_drv_probe) from [] (really_probe+0x280/0x414)
    (really_probe) from [] (driver_probe_device+0x78/0x1c4)
    (driver_probe_device) from [] (bus_for_each_drv+0x74/0xb8)
    (bus_for_each_drv) from [] (__device_attach+0xd4/0x16c)
    (__device_attach) from [] (bus_probe_device+0x88/0x90)
    (bus_probe_device) from [] (device_add+0x3dc/0x62c)
    (device_add) from [] (of_platform_device_create_pdata+0x94/0xbc)
    (of_platform_device_create_pdata) from [] (of_platform_bus_create+0x1a8/0x4fc)
    (of_platform_bus_create) from [] (of_platform_bus_create+0x20c/0x4fc)
    (of_platform_bus_create) from [] (of_platform_populate+0x84/0x118)
    (of_platform_populate) from [] (of_platform_default_populate_init+0xa0/0xb8)
    (of_platform_default_populate_init) from [] (do_one_initcall+0x8c/0x404)

Provide a helper which clearly documents the usage of driver_override.
This will allow later to reuse the helper and reduce the amount of
duplicated code.

Convert the platform driver to use a new helper and make the
driver_override field const char (it is not modified by the core).

Reviewed-by: Rafael J. Wysocki 
Acked-by: Rafael J. Wysocki 
Signed-off-by: Krzysztof Kozlowski 
Link: https://lore.kernel.org/r/20220419113435.246203-2-krzysztof.kozlowski@linaro.org
Signed-off-by: Greg Kroah-Hartman

driver core: platform: Remove platform_device_add_properties()

2021-08-18T14:08:11+00:00

There are no more users for it. The last place where it's
called is in platform_device_register_full(). Replacing that
call with device_create_managed_software_node() and
removing the function.

Reviewed-by: Andy Shevchenko 
Reviewed-by: Thierry Reding 
Signed-off-by: Heikki Krogerus 
Link: https://lore.kernel.org/r/20210817102449.39994-3-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman